Light for use in activating light-activated materials, the light having insulators and an air jacket

ABSTRACT

Light system useful for activating light-activated materials are disclosed. Various configurations of light emitting semiconductor chips and heat sinks are disclosed, as well as various structures and methods for driving, controlling and using them, and materials and structures usable therewith.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application is a continuation-in-part of U.S. patentapplication Ser. No. 10/067,692 filed on Feb. 4, 2002; U.S. patentapplication Ser. No. 10/072,850 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,659 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,853 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,859 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,613 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,302 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,635 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,826 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,858 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,462 filed on Feb. 5, 2002; U.S. patentapplication Ser. No. 10/072,852 filed on Feb. 6, 2002; U.S. patentapplication Ser. No. 10/072,831 filed on Feb. 6, 2002; U.S. patentapplication Ser. No. 10/071,847 filed on Feb. 6, 2002; U.S. patentapplication Ser. No. 10/073,819 filed on Feb. 11, 2002; U.S. patentapplication Ser. No. 10/073,822 filed on Feb. 11, 2002; U.S. patentapplication Ser. No. 10/073,823 filed on Feb. 11, 2002; U.S. patentapplication Ser. No. 10/073,672 filed on Feb. 11, 2002; and U.S. patentapplication Ser. No. 10/076,128 filed on Feb. 12, 2002; each of which isa continuation-in-part of each of U.S. patent application Ser. No.10/016,992 filed on Dec. 13, 2001; U.S. patent application Ser. No.10/017,272 filed on Dec. 13, 2001; U.S. patent application Ser. No.10/017,454 filed on Dec. 13, 2001; and U.S. patent application Ser. No.10/017,455 filed on Dec. 13, 2001; each of which is acontinuation-in-part of U.S. patent application Ser. No. 09/405,373filed on Sep. 24, 1999, now U.S. Pat. No. 6,331,111, and priority isclaimed to each of the foregoing.

[0002] Priority is also claimed to U.S. Provisional Patent ApplicationSerial No. 60/304,324 filed on Jul. 10, 2001.

BACKGROUND

[0003] Lights that may be for activating light-activated materials aredisclosed. There are various materials that are activated by light. Forexample, dental restorative materials, dental sealants and orthodonticadhesives may include monomers and a photoinitiator. The photoinitiatormay be sensitive to light of a particular wavelength, and when exposedto light of that wavelength of sufficient power and duration, activatesthe monomers so that they polymerize into a cured and durable polymer.Further, dental whiteners may be activated or accelerated by exposure toa particular light. In the medical field, light activated materials mayinclude splints, stents, hard tissue restorations, and drugs which areactivated within the human body by exposure to a particular light. Inthe construction field, various adhesives, coatings, insulation, andsealants may be activated by particular light. A particular applicationof such technology would be the activation or curing of structural,repair or coating materials, including underwater application of suchmaterials, or application of such materials in space.

SUMMARY

[0004] Various lights and structures thereof and methods of using themare disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIG. 1 depicts a battery-powered light that uses a single lightemitting diode chip as a light source.

[0006]FIG. 2 depicts a cross-section of the light of FIG. 1.

[0007]FIG. 3 depicts an AC-powered light that uses a single lightemitting diode chip as a light source.

[0008]FIG. 4 depicts a cross section of the light of FIG. 3.

[0009]FIG. 5 depicts a battery-powered light that uses two lightemitting diode chips as a light source.

[0010]FIG. 6 depicts a cross-section of the light of FIG. 5.

[0011]FIG. 7 depicts an AC-powered light that uses two light emittingdiode chips as a light source.

[0012]FIG. 8 depicts a cross-section of the light of FIG. 7.

[0013]FIG. 9 depicts a battery-powered light that uses three lightemitting diode chips as a light source.

[0014]FIG. 10 depicts a cross-section of the light of FIG. 9.

[0015]FIG. 11 depicts an AC-powered light that uses three light emittingdiode chips as a light source.

[0016]FIG. 12 depicts a cross section of the light of FIG. 11.

[0017]FIG. 13 depicts a battery-powered light that uses three or moresemiconductor chip modules mounted on a heat sink in a manner that thelight they emit is collected by a reflector apparatus and focused by alens means onto a light transport mechanism, such as a light guide,plastic stack or fiber.

[0018]FIG. 14 depicts a cross-section of the light of FIG. 13.

[0019]FIG. 15 depicts a variation of the light of FIG. 13, in the lighttransport mechanism is replace by a distally-located mirror whichreflects generally coherent light emitted from the light source in adesired direction for use.

[0020]FIG. 16a depicts a light which uses a plurality of light emittingsemiconductor modules mounted on a heat sink as a light source, afocusing means to produce a generally coherent beam of light, and alight transport means such as optically conductive cable fortransporting light to a location remote from the light source for use.

[0021]FIG. 16b depicts a cross section of the light of FIG. 16a.

[0022]FIG. 17a depicts a gross cross section of a light emitting diodechip that uses an insulative substrate.

[0023]FIG. 17b depicts a gross cross section of a light emitting diodechip that uses a conductive substrate.

[0024]FIG. 18a depicts epitaxial layers of a light emitting diode chipthat uses an insulative substrate.

[0025]FIG. 18b depicts epitaxial layers of a light emitting diode chipthat uses a conductive substrate.

[0026]FIG. 19a depicts a top view of a light emitting diode chip array(single chip) with an insulative substrate.

[0027]FIG. 19b depicts a top view of a top view of a light emittingdiode chip array (single chip) with a conductive substrate.

[0028]FIG. 20a depicts a side view of a chip package for a lightemitting chip that shows a light emitting diode chip with an insulativesubstrate mounted in a well of a heat sink, with electrical connectionsand light emission shown.

[0029]FIG. 20b depicts a perspective view of a chip package for a lightemitting chip with an insulative substrate that shows a chip arraymounted in a well of a heat sink.

[0030]FIG. 21a depicts a side view of a chip package for a lightemitting chip that shows a light emitting diode chip with a conductivesubstrate mounted in a well of a heat sink, with electrical connectionsand light emission shown.

[0031]FIG. 21b depicts a perspective view of a chip package for a lightemitting chip with a conductive substrate that shows a chip arraymounted in a well of a heat sink.

[0032]FIG. 22a depicts a side view of a chip package for a lightemitting chip mounted in a well of a heat sink according to theso-called ‘flip chip’ design, the chip having an insulative substrate.

[0033]FIG. 22b depicts a side view of a flip chip mounted on a flip chippad.

[0034]FIG. 22c depicts a perspective view of a flip chip pad.

[0035]FIG. 22d depicts a perspective view of the chip package of FIG.22a.

[0036]FIG. 23 depicts a side view of a flip chip package with aconductive susbtrate.

[0037]FIG. 24a depicts a side view of a light emitting diode chippackage including the chip (insulative substrate) and heat sink surfacemount arrangement with a protective dome, lens or cover.

[0038]FIG. 24b depicts a side view of a light emitting diode chippackage including the chip (conductive substrate) and heat sink surfacemount arrangement with a protective dome, lens or cover.

[0039]FIG. 25a depicts an array of light emitting chips with insulativesubstrates in surface mount arrangement in a single well of a heat sink.

[0040]FIG. 25b depicts a perspective view of the array ofsurface-mounted chips of FIG. 25a.

[0041]FIG. 26a depicts an array of light emitting chips with conductivesubstrates in surface mount arrangement in a single well of a heat sink.

[0042]FIG. 26b depicts a perspective view of the array ofsurface-mounted chips of FIG. 26a.

[0043]FIG. 27a depicts an array of light emitting chips with insulativesubstrates in surface mount arrangement in individual sub-wells of awell of a heat sink.

[0044]FIG. 27b depicts a perspective view of the array ofsurface-mounted chips of FIG. 27a.

[0045]FIG. 28a depicts an array of light emitting chips with conductivesubstrates in surface mount arrangement in individual sub-wells of awell of a heat sink.

[0046]FIG. 28b depicts a perspective view of the array ofsurface-mounted chips of FIG. 28a.

[0047]FIG. 29a depicts a light emitting surface mount chip packageincluding array of chips, heat sink and protective dome, lens or coveraccording to the chip and surface mount configuration of FIG. 25a above.

[0048]FIG. 29b depicts a light emitting surface mount chip packageincluding array of chips, heat sink and protective dome, lens or coveraccording to the chip and surface mount configuration of FIG. 26a above.

[0049]FIG. 30a depicts a light emitting surface mount chip packageincluding array of chips in sub-wells, heat sink and protective dome,lens or cover according to the chip and surface mount configuration ofFIG. 27a above.

[0050]FIG. 30b depicts a light emitting surface mount chip packageincluding array of chips in sub-wells, heat sink and protective dome,lens or cover according to the chip and surface mount configuration ofFIG. 28a above.

[0051]FIG. 31a depicts a side view of a single surface mount lightemitting diode chip mounted to an elongate heat sink in a manner suchthat light from the chip is emitted at generally a 90 degree angle tothe longitudinal axis of the elongate heat sink.

[0052]FIG. 31b depicts a bottom view of the device of FIG. 31a.

[0053]FIG. 32a depicts a cross-sectional side view of an elongate heatsink having two light emitting semiconductor chips in surface mountconfiguration in an angled orientation in order to present overlappinglight beams for an enhanced density light footprint.

[0054]FIG. 32b depicts a bottom view of the device of FIG. 32a.

[0055]FIG. 33a depicts a cross-sectional side view of an elongate heatsink having three light emitting semiconductor chips mounted on it in anangled orientation in order to present overlapping light beams for anenhanced density light footprint.

[0056]FIG. 33b depicts a bottom view of the device of FIG. 33a.

[0057]FIG. 33c depicts a bottom view of the heat sink of FIGS. 33a and33 b to permit the reader to understand the angular orientation of thelight emitting semiconductor chips.

[0058]FIG. 33d depicts a side view of the heat sink for 3 surfacemounted LED's.

[0059]FIG. 34a depicts a light shield which may be used to shield humaneyes from light emitting by the light.

[0060]FIG. 34b depicts a focus lens which may be used to focus light inorder to present a denser light footprint.

[0061]FIG. 34c depicts a light module with reflective cone installed.

[0062]FIG. 34d depicts a reflective cone.

[0063]FIG. 35 depicts a block diagram of control circuitry that may beused with lights that utilize AC power.

[0064]FIG. 36 depicts by a block diagram of control circuitry that maybe used with lights that utilize battery power.

[0065]FIG. 37 depicts a graph of electrical current input I to the lightemitting semiconductor chip(s) of the light versus time in a pulsedpower input scheme in order to enhance light power output from thechip(s) and in order to avoid light intensity dimunition due to the heateffect.

[0066]FIG. 38 depicts a graph of total light intensity output versustime in order to permit the reader to compare light intensity outputwhen a current input pulsing scheme such as that of FIG. 37 is used to atraditional continuous wave current input approach which generates aheat effect is used.

[0067]FIG. 39 depicts a spectral output of a light with several chips,the chips having different peak wavelengths.

[0068]FIG. 40 depicts overall spectral profile patterns of multi-chiplights in which the chips output different peak wavelengths.

DETAILED DESCRIPTION

[0069] Various light systems useful for activating light-activatedmaterials are disclosed. The invented light systems have application ina variety of fields, including but not limited to medicine and dentistrywhere light-activated materials with a photoinitiator are used. Aphotoinitiator may be used to absorb light of a particular wavelengthand cause polymerization of monomers into polymers.

[0070] Light-activated materials can be applied to a surface and latercured by a variety of methods. One method includes use of a singlephotoinitiator or multiple photoinitiators in the light-activatedmaterial. After the light-activated material has been placed in adesired location, light of a wavelength that activates thephotoinitiator is applied to the light-activated material. The lightactivates the photoinitiator and initiates a desired reaction, such aspolymerization, activation or curing of the light-activated material, orcatalyzing a reaction. For some materials, in order to initiate orcomplete curing, the light used must be of a wavelength to which thephotoinitiator is sensitive, the light should be of a power level thatwill cause curing, and the light should be applied to thelight-activated material for a sufficient duration of time. Although thelight used to activate the photoinitiator should be of a wavelength towhich a photoinitiator is sensitive, the light can come from a varietyof sources, including gas lasers solid state lasers, laser diodes, lightemitting diodes, plasma-arc lights, xenon-arc lights, and conventionallamps. This document discloses light systems that use semiconductorchips as their source of light.

[0071]FIG. 1 depicts a battery-powered light 100 that uses a singlelight emitting diode chip as a light source. FIG. 2 depicts across-section of the light 100 of FIG. 1. The portable light system 100includes a light source module 102 which generates light of a desiredwavelength or multiple wavelengths for activating a photoinitiator ormultiple photoinitiators and initiating curing of a light activatedlight-activated material. The light source module 102 has a light shield103 for blocking light generated by the light emitting semiconductorchip(s) 150 from reaching human eyes and skin. The apparatus 103 couldalso be configured as a lens or focusing cone for modifying thefootprint of light emitted by the light. The light emittingsemiconductor chip(s) 150 are located at the distal end of the light,and at the distal end of the light source module 102. The chip(s) 150are oriented to emit light at generally a right angle with thelongitudinal axis of the light source module or the longitudinal axis ofthe light handpiece, although chips could be mounted to emit light atfrom about a 45 degree angle to about a 135 degree angle with thelongitudinal axis of the light source module, heat sink, or handpiece asdesired. The light system 100 includes a housing 104 for containing andprotecting electronic circuits and a DC battery pack. In some lights,the light emitting semiconductor chip(s) may be powered by from lessthan about 25 milliamps to more than about 2 amps of electrical current.Many lights can have chip(s) powered from about 350 milliamps to about1.2 amps of current. Higher power lights may often use more than about100 milliamps of current.

[0072] A switch 105 a is provided on the top of the housing 104 facing adirection opposite from the direction that light would be emitted fromthe light source module 103. A second switch 105 b is provided on theside of the housing. The switches 105 a and 105 b are devices such as abutton or trigger for turning the light emission of the light on andoff. A timer 106 is provided to control the duration of time that thelight emits a beam of light. Control buttons to set and adjust the timerare depicted as 151 a and 151 b.

[0073] An audible indicator or beeper may be provided in some lights toindicate when light emission from the light begins and ends. A firstlight emitting diode indicator lamp 107 is located on the housing in avisible location in order to indicate to the user low battery power. Asecond light emitting diode indicator lamp 108 is located on the housingin a visible location in order to indicate to the user that the batteryis being charged. A main on/off switch to the light 160 is provided atthe rear or proximal end of the housing. A wavelength selector may beprovided in some lights so that the user may select the wavelength oflight that he wishes to emit from the light, depending on the wavelengthsensitivity of the photoinitiator in the light-activated material thathe is using. The user may also select a combination of two or morewavelengths of light to be emitted together in some lights.

[0074] A separate battery charger module 109 may be included in order toreceive AC power from a traditional wall socket and provide DC power tothe light system for both charging the batteries and powering the lightsource and control circuitry when the batteries if desired. The batterycharger module 109 has a cable 109 a and a plug 109 b for plugging intoa receptacle or connector 170 on the proximal end of the light housing104. The battery charger module 109 includes circuitry 109 c forcontrolling battery charging of batteries 166.

[0075] The light module 102 has a casing 161 that encases an elongateheat sink 162. The casing 161 is separated from the heat sink 162 by abuffer layer 163 such as insulation tape and an air space or air jacketmay be provided therebetween for heat dissipation. Electricallyconductive wires 164 to power the light-emitting semiconductor chip(s)150. Internally, we can see that the heat sink 162 is an elongate andcurved structure which positions a semiconductor chip at its end in aconvenient place for use without a light guide. At the distal end of theheat sink 162, there may be a smaller primary heat sink or semiconductorchip module which includes a smaller primary heat sink. A semiconductormodule may be covered by a protective cover or dome or a focus lens. Theheat sink 162 may be an elongate structure or other shape as desired.Use of an elongate heat sink 162 rapidly transfer heat away from thechip(s) 150 for heat dissipation. If heat transfer and dissipation arenot handled adequately, damage to the chip(s) 150 may result, or lightoutput of the chip(2) 150 may be diminished.

[0076] The light source module 102 is removable from the housing 104 andinterfaces therewith and mounts thereto by a connection plug 165. One ormore batteries 166 are provided to power the light during use. The lightmay have control circuitry 167 located in the housing 102. Batterycharger 109 c is located in the power supply 109 for controlling batteryrecharging and direct powering of the light from wall outlet power whenthe batteries are low. The power supply 109 has an AC plug 109 d.

[0077] A unique advantage of some of the light systems depicted hereinis that most or all components of the light system, including the lightsource, batteries, control circuitry and user interface, areconveniently located in or on a handpiece. This results in a veryportable, yet compact and easy to use light system. Only when thebatteries are being charged would the user need to have a cord attachedto the light system or even be in the vicinity of AC power. In the caseof a battery-less light system, the batteries would be omitted and thelight system would be connected to a power source by an electrical cord.It would also be possible for the light system to be operated usingpower from a battery charger when the battery pack is being charged orwhen no batteries are being used.

[0078]FIG. 3 depicts an AC-powered light that uses a single lightemitting diode chip as a light source. FIG. 4 depicts a cross section ofthe light of FIG. 3. Referring to these figures, a light system 301 isdepicted. The light system 301 includes a handpiece or wand 302, cabling303, and a power supply 304 with an AC plug 304 a. Light controlcircuitry 304 b may be located within the power supply 304 and is remotefrom the wand 302 in order to keep the wand compact and light weight.The handpiece or wand 302 has minimum size, weight and componentry forconvenience of use. The handpiece 302 includes a housing 305, an on/offswitch or light output control 306, an integral light source module 307,and a device 309 which may be a light shield, light reflective cone orfocus lens. The handpiece 302 receives electrical power from cabling303. A cable strain relief device 308 may be provided. A timer 310 maybe provided with timer adjustment buttons 311 and 312 in order tocontrol timed duration of light output from the light. All controlcircuitry 304 b is located in a module remote from the handpiece 302.

[0079] Referring to the cross section of FIG. 4, it can be seen that theheat sink 401 may be configured as an elongate device with a planarmounting platform on its distal end for mounting chips or chip modulesthereto. The heat sink has a longitudinal axis, and the light emittingsemiconductor chip(s) may be oriented at an angle with the longitudinalaxis of the heat sink from about 45 to about 135 degrees. In somelights, the chips may be oriented to emit light at an angle with theheat sink longitudinal axis of 70 to 110 degrees, 80 to 100 degrees, orabout 90 degrees. The heat sink distal end may be curved as desired toposition a light emitting semiconductor device 401 thereon to bepositioned in a location for convenient use. The semiconductor device402 may be covered with a protective window, dome or focus lens 403. Theheat sink may occupy less than 50% of the length of the wand, more than50% of the length of the wand, 60% of the length of the wand, 70% of thelength of the wand, 80% of the length of the wand, 90% of the length ofthe wand, or up to 100% of the length of the wand. Electrical wire 404provides power to the light emitting semiconductor device 402.Insulation means or insulators 405 such as rubber insulators orinsulation tape separate the heat sink 401 from the casing 305 andprovide for airspace or an air jacket 406 therebetween for ventilationand heat dissipation. The insulators may be of any suitable materialthat will provide spacing and distance between the heat sink and thecasing or housing to form an air jacket therebetween and permit aircirculation, ventilation and heat dissipation. The insulators could berubber, silicone, plastic or other materials. The light housing may haveone or more vents to permit or encourage air to travel from outside thehousing into the air jacket, and/or to permit or encourage air from theair jacket to travel outside of the housing. Air exchange can assist incooling functions. The air jacket can assist in avoiding a buildup ofheat in the handpiece, wand or housing that could cause user discomfort.

[0080]FIG. 5 depicts a battery-powered light 501 that uses two lightemitting diode chips as a light source. FIG. 6 depicts a cross-sectionof the light 501 of FIG. 5. The light 501 includes a housing or casing502 for containing and protecting the light components. A series ofvents 503 are provided in the housing 502 to permit heat to escapetherefrom and to permit air circulation therein. At the distal end ofthe housing 502, a light module 504 is provided. The light module 504may include an angled tip and may be removable and replaceable withother light modules of differing characteristics as desired. A lightshield, light reflective cone or focus lens 505 is provided at thedistal end of the light module 504. At the proximal end of the light501, a handle 506 is provided for grasping the light. An on-off switchor trigger 507 is provided on the distal side of the light handle 506for effecting light emission. On the proximal side of the light handle506, a main switch 507 for powering up the light 501 is located. A timer509 with timer adjustment buttons 510 and 511 is provided to time theduration of light output. Indicator lights 512 and 513 are provided toindicate low battery and battery charging. A battery charger module 520is provided with a power supply 521, cable 522 and plug 523. The plugfits into receptacle 601 for charging the battery 602 of the light 501.

[0081] Referring to FIG. 6, light module 504 includes a casing 603 thatcontains an elongate heat sink 604 that is separated from the casing 603by insulators 605 to form a ventilating and heat-dissipating air space606 therebetween. Heat sink 604 may include a thermoelectric coolermaterial 608 thereon for enhanced heat dissipation. Electrical wires 607power a pair of light emitting semiconductor devices or modules 609 aand 609 b. The semiconductor devices 609 a and 609 b are mounted on theheat sink 604 at a mounting receptacle 611 that has two adjacent angledplanes oriented to cause the light output beams from the semiconductordevices 609 a and 609 b to overlap to provide an overlapped and enhancedintensity light footprint 610. The mounting planes are oriented at anangle of from about 10 to about 180 degrees with respect to each other.The light 501 also includes a timer 509 with timer control buttons 621and 622, and electronic control circuitry 623. A battery pack 602 islocated inside casing 502 to provide operating power. The light module504 is connected to housing 502 using an electrical plug 624. The lightmodule 504 can therefore be unplugged and replaced with another lightmodule of different power characteristics or which emits a differentwavelength of light for different usage applications.

[0082]FIG. 7 depicts an AC-powered light 701 that uses two lightemitting diode chips as a light source. FIG. 8 depicts a cross-sectionof the light 701 of FIG. 7. The light system 701 includes a handpiece orwand 702, cabling 703, and a power supply 704 with an AC plug 704 a.Control circuitry 704 b is located within the power supply 704 and isremote from the wand 702 in order to keep the wand compact and lightweight. The handpiece or wand 702 has minimum size, weight andcomponentry for convenience of use. The handpiece 702 includes a housing705, an on/off switch or light output control 706, an integral lightsource module 707, and a light shield 709. The handpiece 702 receiveselectrical power from cabling 703. A cable strain relief device 708 maybe provided. A timer 710 may be provided with timer adjustment buttons711 and 712 in order to control timed duration of light output from thelight. All control circuitry 704 b is located in a module remote fromthe handpiece 702. Referring to the cross section of FIG. 8, it can beseen that the heat sink 801 may be configured as an elongate device witha longitudinal axis shared with the longitudinal axis of the wand. Thelight emitting semiconductor chip 802 and 803 are mounted to the heatsink 801 at an acute angle to each other in order to produce anoverlapping and enhanced intensity light footprint. The heat sink distalend may be curved as desired to position the light emittingsemiconductor devices thereon for convenient use. The semiconductordevices 803 and 803 may be covered by a protective window, dome or focuslens. The heat sink may occupy less than 50% of the length of the wand,more than 50% of the length of the wand, 60% of the length of the wand,70% of the length of the wand, 80% of the length of the wand, 90% of thelength of the wand, or up to 100% of the length of the wand. Electricalwire 804 provides power to the light emitting semiconductor devices 802and 803. Insulation means 805 such as rubber insulators or insulationtape separate the heat sink 801 from the casing 705 and provide forairspace 806 therebetween for ventilation and heat dissipation. Aconnection plug 810 is provided for connecting the power module to thelight. Thermoelectric cooler material 820 is optionally provided on theheat sink for enhanced cooling.

[0083]FIG. 9 depicts a battery-powered light 901 that uses three lightemitting diode chips or modules as a light source. FIG. 10 depicts across-section of the light 901 of FIG. 9. The componentry of this lightis as generally described previously except for its three light emittingdiode light source structure. It uses three light emitting diode chipsor chip modules 902 a, 902 b and 902 c arranged in complementary angledconfiguration so that the light beams emitted by each overlap at adesired distance from the light source to form an overlapped andenhanced intensity light footprint 903. The arrangement of 3 LED's isdescribed elsewhere in this document.

[0084]FIG. 11 depicts an AC-powered light 1101 that uses three lightemitting diode chips or modules as a light source. FIG. 12 depicts across-section of the light 1101 of FIG. 11. The componentry of thislight is as generally described previously except for its three lightemitting diode light source structure. It uses three light emittingdiode chips or chip modules 1102 a, 1102 b and 1102 c arranged incomplementary angled configuration so that the light beams emitted byeach overlap at a desired distance from the light source to form anoverlapped and enhanced intensity light footprint 1103.

[0085]FIG. 13 depicts a battery-powered curing 1301 light that uses aplurality of semiconductor chip modules mounted on a heat sink in amanner that the light they emit is collected by a reflector apparatusand focused by a lens means onto a light transport mechanism, such as alight guide, plastic stack or fiber 1302. FIG. 14 depicts across-section of the light 1301 of FIG. 13. Many of the components ofthis light are as discussed previously for other lights, and thatdiscussion is not repeated here. However, the light source and lighttransport means are very different from lights discussed above. Thelight 1301 includes a housing 1303 which has a light transport means1302 such as a light guide, plastic stack or fiber attached to it. Thelight transport means 1302 transports light from a light module to aremote location for use. The light transport means 1302 depicted has acurved distal portion 1304 to cause light 1305 to be emitted in adesired direction, such as at a right angle to the longitudinal axis ofthe light or the light transport means. The light transport means may beremovable and replaceable with light guides of different lengths andconfigurations. A gross or secondary heat sink 1405 is provided for heatremoval from the system. The secondary heat sink 1405 has a proximalside on which a thermoelectric material layer 1406 may be placed toenhance heat removal ability. Optionally, a fan 1407 may be provided toimprove heat removal efficiency, and vents may be provided in thehousing to encourage air circulation. The secondary heat sink 1405 mayhave mounted directly or indirectly to it a plurality of semiconductorlight emitting chips or chip modules 1409. Those chips 1409 may bemounted to a primary heat sink such as 1410. light emitted by the chips1409 will be reflected by a reflector device 1411 such as a mirroredparabolic reflector to an optional lens or focusing device 1412 whichfocuses a generally coherent light beam onto the light transport means1302. The reflector may be of a desired shape for directing light, suchas frusto-conical, parabolic or otherwise. If the light emitting devicesare oriented so that the light which they emit is substantially directedtoward the distal end of the light, the reflector may be omitted. Abattery pack 1415 and control circuitry 1413 are provided.

[0086]FIG. 15 depicts an alternative configuration of the light of FIG.13. The light 1501 has no light transport mechanism and instead has alight exit tube 1502 that has a distal end with a mirror or reflector1504 which can reflect a generally coherent light beam 1503 to a lightexit 1505 in a desired direction for use, such as at a generally rightangle to the longitudinal axis of the light module or the light.

[0087]FIG. 16a depicts a light light 1601 that has a light source andcontrol module 1602 remotely located from a handpiece 1603 connected bya connection means 1604 that includes an optically conductive cable andelectrical wires for electrical connection. FIG. 16b depicts a crosssection of the light of FIG. 16a. The light source and control module1602 includes a housing 1610 with optional air vents thereon, electroniccontrol circuitry 1611, an electrical cord with power plug 1612, acooling fan 1613 for air circulation and heat dissipation, a heat sink1615 which may be appropriately shaped to accept light emittingsemiconductor devices on its distal side, such as having a concavehemispherical or parabolic portion, and having a thermoelectric cooler1616 on its proximal side for enhanced heat dissipation. A plurality oflight emitting semiconductor devices such as LED chip modules 1618 aremounted to the heat sink distal side so that they emit light into anoptical system such as a focus lens 1619 which places a generallycoherent light beam onto the optically conductive cable where it istransported to a distant handpiece 1603 that includes a housing 1651,light exit 1650 for permitting light to be delivered to alight-activated material to be cured, and various controls such as lighton/off control 1660, timer display 1663, and timer adjustment buttons1661 and 1662. The distal end of the handpiece housing 1670 may beangled from the longitudinal axis of the handpiece in for convenience oflight application to a light-activated material. The remote light sourceemployed by the light in FIGS. 16a and 16 b permit a larger and veryhigh power light source, such as one which provides 800 mw/cm² to 2000mw/cm² output from the handpiece.

[0088] As desired in various lights, the light source may be a singleLED chip, single LED chip array, an array of LED chips, a single diodelaser chip, an array of diode laser chips, a VCSEL chip or array, or oneor more LED or diode laser modules. The wavelength of light emitted fromthe semiconductor light source can be any desired wavelength orcombination of different wavelength, depending on the sensitivity of thephotoinitiator(s) in the light-activated material to be cured. Any ofthe semiconductor and heat sink arrangements described herein may beused to construct desired lights.

[0089] Referring to FIG. 17a, a light emitting diode (“LED”) chip 1701is depicted in which the LED structure 1702 has been grown on top of oron one side of an insulative substrate 1703. Electrodes 1704 a and 1704b are provided to power the LED. In such a structure, all electrodeswill be located on the top surface of the LED. light is emitted from allsides of the LED as depicted.

[0090] A similar LED chip 1710 with a conductive substrate 1711 andaccompanying LED structure 1712 and electrodes 1713 and 1714 is depictedin FIG. 17b.

[0091]FIG. 18a depicts an example of epitaxial layer configuration 1801for an LED with an insulative substrate used in lights depicted herein.The LED includes an electrically insulative substrate such as sapphire1802. The substrate serves as a carrier, pad or platform on which togrow the chip's epitaxial layers. The first layer placed on thesubstrate 1802 is a buffer layer 1803, in this case a GaN buffer layer.Use of a buffer layer reduces defects in the chip which would otherwisearise due to differences in material properties between the epitaxiallayers and the substrate. Then a contact layer 1804, such as n-GaN, isprovided. A cladding layer 1805 such as n-AlGaN Sub is then provided.Then an active layer 1806 is provided, such as InGaN multiple quantumwells. The active layer is where electrons jump from a conduction bandto valance and emit energy which converts to light. On the active layer1806, another cladding layer 1807, such as p-AlGaN is provided that alsoserves to confine electrons. A contact layer 1808 such as p+ GaN isprovided that is doped for Ohmic contact. The contact layer 1808 has apositive electrode 1809 mounted on it. The contact layer 1804 has anegative electrode 1810.

[0092]FIG. 18b depicts epitaxial layer configuration 1850 for an LEDwith a conductive substrate. The LED includes an electrically conductivesubstrate such as SiC 1852 that has an electrode 1851 on it. Thesubstrate serves as a carrier, pad or platform on which to grow thechip's epitaxial layers, and as a negative electrode in the chip. Thefirst layer placed on the substrate 1852 is a buffer layer 1853, such asn-GaN. A cladding layer 1854 such as n-AlGaN is provided followed by anactive layer 1855 such as InGaN with multiple quantum wells. That isfollowed by a cladding layer 1856 such as p-AlGaN and finally a contactlayer 1857 such as p+ GaN that has an electrode 1858 mounted on it.

[0093]FIG. 19a depicts a top view of a single chip array, such as an LEDchip array on a single chip 1901 (in contrast with an array of singlechips) with a size a×b on an insulating substrate. The size of a and bmay each be greater than 300 micrometers, or may each be greater than 1millimeter if desired. Semiconductor materials 1904 are located on anelectrically insulative substrate (not shown). Positive and negativeelectrode pads are provided, each in electrical connection with itsrespective metal electrode strip 1902 and 1903 arranged in a row andcolumn formation (8 columns shown) to create the array and power thechip. This structure enables the LED to emit light of greater power thanthat which is possible in a non-array traditional chip. The electrodelayout of FIG. 19a is called a ‘comb’ layout.

[0094]FIG. 19b depicts a top view of an semiconductor chip array, suchas an LED chip array, on a single chip 1950 with a size a×b, on aconductive substrate. Each of sizes a and b may greater than 300micrometers, or as desired, each of a and b may be greater than 1millimeter. Semiconductor materials 1952 are located on an electricallyconductive substrate (not shown). Positive electrode pads are providedin electrical connection with a metal strip 1951 arranged in an arrayformation to power the chip. The substrate serves as the negativeelectrode in this depiction. When LED arrays, or chip arrays (as opposedto an array of chips) such as those depicted are used in a curing light,the light source may be a single chip array, a pair of chip arrays, ormultiple chip arrays such as 3 or more chip arrays. The chip arrays maybe designed to output any particular desired wavelength and intensitylevel of light.

[0095] Referring to FIG. 20a, a side view of a surface mount LED chippackage 2000 including the LED chip 2001 on a heat sink 2002 isprovided. The LED chip depicted has an insulating substrate and ismounted in a well 2004 of the heat sink 2002 by the use of heatconductive and light reflective adhesive 2003. light is emitted by thechip in all directions, and light which is emitted toward the adhesive2003 or the well walls is reflected outward in a useful direction 2020.The chip is electrically connected via wires 2010 a, 2010 b, 2010 c and2010 d using intermediary islands 2011 and 2012. The LED chip is locatedin a circular well 2004 of the heat sink 2002. The circular well isformed with sides or walls at about a 45 degree angle or other desiredangle (such as from about 170 to about 10 degrees) so that light emittedfrom the side of the chip will be reflected from the walls of the wellin a desired direction as indicated by arrows in the figure. This allowsthe highest possible light intensity to be obtained using a chip ofgiven size. The well walls may have a light reflective coating toincrease efficiency.

[0096] Referring to FIG. 20b, a perspective view of a LED chip array(single chip) chip package 2050 including the chip array 2051 on aninsulative substrate in a well 2052 of a heat sink 2053 is depicted.

[0097] Referring to FIG. 21a, a side view of an LED chip module 2100 isprovided. An LED chip 2101 with a conductive substrate is mounted in acircular well 2103 of a heat sink 2104 by use of heat conductive lightreflective adhesive 2102. A negative electrode 2110 is provided on theheat sink. Positive electrical connection is provided by wires 2105 and2106, and island 2107.

[0098] Referring to FIG. 21b, a chip array package 2150 that includes anLED chip array 2151 with a conductive substrate mounted in a well 2152of a heat sink 2153 with an electrode 2154 and wire connection 2155 isdepicted.

[0099]FIG. 22a depicts a side view of a chip package 2200 for a lightemitting diode chip array 2201 mounted in a well 2202 of a heat sink2203 according to the so-called ‘flip chip’ design, the chip having aninsulative substrate. FIG. 22b depicts a side view of a flip chip 2201mounted on a flip chip pad 2204. FIG. 22c depicts a perspective view ofa flip chip pad 2204. FIG. 22d depicts a perspective view of the chippackage 2200 of FIG. 22a. Intermediate islands or electrode pads 2201 aand 2210 b are provided on the flip chip pad to ease of electricalconnection with the chip. Electrode bumps 2111 a and 2111 b are providedbetween the chip and the pad for electrical connection. The chip has anelectrode 2201 b on top and its epitaxial layers 2201 a facing downtoward the pad 2204 and the bottom of the well 2202. The pad 2204 uppersurface is light reflective so that light is reflected from the pad in auseful direction. The pad 2204 may be coated with a light reflectivefilm, such as Au, Al or Ag. In such a package, all of the light emittedfrom the chip can be reflected back in the light exit direction forhighest light output.

[0100]FIG. 23 depicts a flip chip package 2301 in which a chip 2302 witha conductive substrate is mounted upside down (electrode up) on a flipchip pad 2303 with light reflective and heat conductive adhesive 2304 inthe well of a heat sink. Electrical connection takes advantage of theexposed electrode of the chip 2302.

[0101] Referring to FIG. 24a, a high power LED package 2401 is depictedusing a chip 2402 with an insulative substrate mounted in the well of aheat sink 2403 using heat conductive and light reflective adhesive 2404.The heat sink is surrounded by a known insulating material 2405 thatserves the purpose of protecting electrode and dome connections. Thewalls and bottom of the well may be polished to be light reflective, ormay be covered, plated, painted or bonded with a light-reflectivecoating such as Al, Au, Ag, Zn, Cu, Pt, chrome, other metals, plating,plastic and others to reflect light and thereby improve light sourceefficiency. Electrodes and/or connection blocks are provided forelectrical connection of the chip. An optical dome or cover 2410 mayoptionally be provided for the purpose of protecting the chip and itsassemblies, and for the purpose of focusing light emitted by the chip.The dome may be made of any of suitable material such as plastic,polycarbonate, epoxy, glass and other suitable materials. Theconfiguration of the well and the dome provide for light emission alongan arc of a circle defined by φ. The dome 2410 may serve the function ofprotecting the chip(s) from dirt, moisture, contaminants and mechanicaldamage. It may also serve the function of focusing light emitted by thechip(s) or otherwise modifying the light beam to a desired configurationor footprint. FIG. 24b depicts a similar arrangement for a chip package2450 in which the chip 2454 has a conductive substrate and thus whenmounted to the heat sink 2452 can use an electrode 2455 on the heat sinkitself for electrical connection. Protective dome 2451 and insulatingcovering 2453 are provided.

[0102] Referring to FIGS. 25a and 25 b, a chip package 2501 is providedwith an array of light emitting semiconductor chips 2504 a, 2504 b, etc.having electrically insulative substrates located in a single well 2502of a heat sink 2503. The chips are mounted by an electrically conductiveand heat conductive adhesive 2605. The chips are electrically connectedto each other by wires 2505 a, 2505 b, etc.

[0103] Referring to FIGS. 26a and 26 b, a chip package 2601 is providedthat has a heat sink 2602 with a single well 2603 and an array of LEDchips 2604 a, 2604 b, etc. in the well 2603. The chips have electricallyconductive substrates and an electrode 2606 is provided on the heatsink.

[0104] Referring to FIG. 27a, a chip package 2701 is depicted with anarray of LED chips 2702 a, 2702 b, 2702 c, etc. is depicted, with eachchip located in its own individual sub-well 2703 a, 2703 b, 2703 c in agross well 2704 of a heat sink 2705. The chips have electricallyinsulative substrates.

[0105] Referring to FIG. 27b, a chip package 2750 is depicted that hasan array of LED chips 2763 a, 2763 b, 2763 c with electricallyconductive substrates. Each LED chip is mounted in its own individualsub-well, all located within a gross well 2761 of a heat sink 2762.

[0106]FIGS. 28a and 28 b depict a chip package 2801 that has a heat sink2802 with a gross well 2803 and a plurality of sub-wells 2804 therein,each sub-well having a light emitting chip 2805 with a conductivesubstrate within it. The heat sink 2803 has a negative electrode 2806for electrical connection.

[0107] Referring to FIG. 29a, an LED chip module 2901 is depicted thathas an array of LED chips 2902 a, 2902 b, etc located in a well 2903 ofa heat sink 2904. Insulative covering 2910 as well as a cover or dome2911 are provided respectively. The chips of FIG. 29a have insulativesubstrates.

[0108] Referring to FIG. 29b, an LED chip module 2950 is depicted thathas an array of LED chips 2951 a, 2951 b, etc. located in a well 2955 ofa heat sink 2954. Insulative covering 2960 as well as a cover or dome2961 are provided respectively. The chips of FIG. 29b have conductivesubstrates and an electrode 2959 is provided on the heat sink.

[0109] Referring to FIG. 30a, an LED chip module 3001 is depicted thathas an array of LED chips 3002, with each chip in a sub-well 3003 of agross well 3006 of a heat sink 3005 and the entire module covered by aprotective or focus dome 3012. The chips have electrically insulativesubstrates.

[0110] Referring to FIG. 30b, an LED chip module 3050 is depicted thathas an array of LED chips 3051, with each chip in a sub-well 3052 of agross well 3055 of a heat sink 3054 and the entire module covered by aprotective or focus dome 3061. The chips have electrically conductivesubstrates and there is an electrode 3056 on the heat sink.

[0111] Referring to FIGS. 31a and 31 b, side and bottom views of asurface mount chip configuration are depicted for mounting a single LED3100 or LED module (as described previously) to an elongate heat sink3101. Electrically conductive wires 3102 a and 3102 b and electrodes3103 a and 3103 b are provided for powering the LED. The LED is mountedon a platform 3104 formed on the heat sink distal end. Mounting isachieved by use of light reflective and heat conductive adhesive 3105. Acover or focus dome 3106 is provided over the LED. The heat sink has alongitudinal axis, and the LED is mounted so that the average beam oflight that it emits is generally at a 45 to 135 degree angle with thataxis, and in some instances at a right angle to it.

[0112]FIGS. 32a and 32 b depict side and bottom views of an elongateheat sink 3201 having two light emitting semiconductor chips or modules3202 and 3203 mounted on mounting platforms 3204 a and 3204 b usingadhesive 3205 a and 3505 b (such as heat conductive or light reflectiveadhesive). The chips are mounted on the heat sink in an angledorientation with respect to each other in order to present overlappinglight beams for an enhanced density light footprint 3204. The angle oforientation of the chips is depicted as θ which can be from zero to 180degrees, or from 30 to 150 degrees, or from 45 to 135 degrees, or from70 to 110 degrees, or from 80 to 100 degrees or about 90 degrees, asdesired. The chips are offset from each other by a desired distance ‘a’,which can range from zero to any desired distance. Wires and electrodesare provided to power the LED's. An optional thermoelectric cooler 3208may be provided to enhance heat removal.

[0113]FIG. 33a depicts a cross-sectional side view of a light modulethat uses three light emitting chips or chip modules. FIG. 33b depicts abottom view of the same. FIG. 33c depicts a bottom view of the heat sinkand mounting platform arrangement. FIG. 33d depicts a side view of theheat sink and mounting platform arrangement. An elongate heat sink 3301is provided having three light emitting semiconductor chips or modules3302, 3303, and 3304 mounted on mounting platforms in an angledorientation with respect to each other in order to present overlappinglight beams for an enhanced density light footprint 3306. The mountingplatforms depicted are generally planar and are arranged to present thedensest useful light footprint. The modules may each include their ownprimary heat sink. The modules or chips may be mounted to the elongateheat sink using a heat conductive or light reflective adhesive asdesired. Electrical wires and electrodes are used to power the chips ormodules. An optional thermoelectric cooler 3308 may be provided. Themounting platforms 3305 a, 3305 b and 3305 c can be seen more clearly inFIGS. 33c and 33 d. The mounting platforms depicted are arranged incircular fashion at an angular offset θ with respect to each other,which in this case is 120 degrees. More mounting platforms could beused, and any desired arrangement of the mounting platforms could beaccommodated. In FIG. 33d it can be seen that the mounting platforms3305 a, 3305 b and 3305 c are arranged at an angle φ with thelongitudinal axis of the heat sink 3301. The angle φ can be from 0 to 90degrees, from 10 to 80 degrees, from 20 to 70 degrees, from 30 to 60degrees, from 40 to 50 degrees, or about 45 degrees as desired togenerate the densest usable light footprint.

[0114]FIG. 34a depicts a light shield 3401 which may be used inconjunction with lights depicted herein to shield human eyes from lightemitting by the light. The light shield includes an orifice 3403 throughwhich light from a light may pass, the receptacle 3403 being formed bythe light shield body 3402. A flare 3404 of the shield performs most ofthe protective function.

[0115]FIG. 34b depicts a focus lens 3402 which may be used to focuslight emitted by lights depicted herein in order to present a denserlight footprint. The focus lens has an outer periphery 3405, a lightentrance side 3506 and a light exit 3507. The focus lens may be designedaccording to known optical principles to focus light output from chipswhich may not be in an optimal pattern for use in curing.

[0116]FIG. 34c depicts a reflection cone 3408 in conjunction with LEDmodule 3409, which is mounted on a heat sink 3910 by using heatconductive adhesive 3411. One or more connection wires 3412 may beprovided to power the LED module 3409. The purpose of the lightreflective cone is to re-shape the light beam from the LED module tocreate a light footprint of desired size and density. The inner wall ofthe cone 3408 may be coated with a highly reflective material, such asthe reflective materials mentioned elsewhere in this document. The lightbeam from the LED module will change its path and configuration due tobeing reflected by the cone 3408.

[0117] A detailed depiction of the light reflective cone 3408 isprovided in FIG. 34d, which illustrates a cross-sectional view of thecone. An opening with an appropriate diameter “a” is provided at theproximal side of the cone for fitting to a light module of a light. Thediameter “a” is chosen as an appropriate size for permitting light toenter therein. The cone has a total length “b”. Adjacent light entranceat “a”, a cylindrical portion of the cone is provided having alongitudinal length “c”. Following cylindrical portion “c”, there is afrusto-conical section of the cone interior having a length “b” minus“c”. A light exit is provided at the end of the cone opposite the lightinlet. The light exit has a diameter “d”, where in many lights, “d” willbe smaller than “a”. The exterior diameter of the cone at its point ofattachment to a light module is “e”, where “e” is greater than “a”. Asdesired, the various dimensions of the cone as well as its basicgeometry (such as conical, frusto-conical, cylindrical, parabolic, etc.)are selected to achieve a desired light footprint size and density. Atleast some portion of the interior surfaces of the reflective cone mayhave the ability to reflect light to aid in increasing the density of alight footprint. Appropriate reflective surfaces are mentioned elsewhereherein. Example dimensions of the various portions of the reflectivecone in one light are as follow: a=from about 5 mm to about 8 mm; b=fromabout 5 mm to about 8 mm; c=from about 2 mm to about 3 mm; d=from about4 mm to about 6 mm; e=from about 8 mm to about 10 mm. Actual structureand dimensions of a reflective cone or reflective attachment or lightexit for a light may vary depending on product type and application anddesign choice.

[0118]FIG. 35 depicts a logic diagram 3501 of circuitry that may be usedby AC-powered versions of the invented lights. AC power input 3502 isprovided to a power switch source 3503 which outputs DC power to a mainswitch 3504. Main switch 3504 powers the control circuit 3505 and theoptional TE cooler 3506 if so equipped. Main switch 3504 also provides aconstant current source 3507 for the timer 3508, timer setup 3511, timeractivation switch 3572 and optional light output beeper 3513. Constantcurrent source 3507 also powers the light source 3509 to accomplishlight output 3510.

[0119] Referring to FIG. 36, a logic diagram 3601 of circuitry that maybe used by battery-powered versions of the invented lights is depicted.AC power input 3602 is provided to a power switch source 3603 whichoutputs DC power to a battery charge unit 3604 that charges battery3605. The battery 3605 powers main switch 3507. Main switch 3607 powersthe control circuit 3608 that controls the optional TE cooler 3610 andthe fan 3609. Main switch 3607 also provides a constant current source3611 for the timer 3613, timer setup 3614, timer activation switch 3615and optional light output beeper 3616. Constant current source 3611 alsopowers the light source 3612 to accomplish light output. An electricalvoltage booster 3617 may be provided to increase the voltage from thebattery to meet electrical requirements of the light source.

[0120] Referring to FIG. 37, a graph of electrical current input I tothe light emitting semiconductor chip(s) of the light versus time in apulsed power input scheme is depicted. FIG. 38 depicts a graph of totallight intensity output versus time in order to permit the reader tocompare light intensity output when a current input pulsing scheme suchas that of FIG. 37 is used to a traditional continuous wave currentinput approach which generates a heat effect is used. A pulsed currentinput scheme may be used in order to enhance light power output from thechip(s) and in order to avoid light intensity reduction due to the heateffect. It has been found that when operated in continuous wave mode,the heat effect or heat buildup in the light emitting semiconductorchips will cause a decrease in light output intensity over time, until astabilized light output yield is reached 3802 at point in time 3803. Incontrast, when current input to the semiconductor light source ispulsed, a greater even level of light power output with greaterintensity is achieved 3801. Laboratory experiments have shown thisincrease “d” to be more than 20% in lights, providing significantlyincreased light yield and stable light intensity output in exchange fora simple control modification. Each of the square waves in FIG. 37 is apulse of current input to the semiconductor light source, measured by“a=duration”, “b=rest period”, and “c=current input level (amps.)”.These criteria can be adjusted depending on the curing environment, orpulsed current input to the light source could be omitted in favor ofcontinuous wave current input. It has also been found that pulsed poweroutput from the light (not shown in the figures) may be desirable insome circumstances. Pulsed power output from the light can avoidoverloading photoinitiators in the material to be cured with photons,and permitting them to initiate polymerization of a light-activatedmaterial in a stable fashion.

[0121] Referring to FIG. 39, a graph showing the spectral output of alight with numerous chips, the chips having differing peak spectraloutputs, is provided. Some light-activated materials, such as dentalcomposites may include more than one photoinitiator. The photoinitiatorsmay be sensitive to light of different wavelengths. Even though lightemitted by single semiconductor chip can cover many photoinitialtors, asingle semiconductor chip may not provide broad enough spectral outputto cover the full range of possible photoinitiators that may be presentin a particular light-activated material. Referring to previous figures,it is possible to construct a curing light that has numerouslight-emitting semiconductor chips, at least several of which havediffering spectral outputs, such as is depicted in FIG. 39. For example,LED1 could peak at about 325 nm, while LED2 peaks at about 350 nm, etc.to LED n which peaks at 575 nm. Of course many other configurations andspectral outputs are possible depending on the particular use of thelight. The arrangement of the light emitting semiconductor chips can bevaried according to the light beam pattern needed.

[0122] Depending on number and type of light emitting semiconductorchips used, per FIG. 39, an overall spectrum profile pattern, such asProfile 1, Profile 2, and Profile n of FIG. 40 can be achieved. Theseparticular spectral profiles are provided by way of example only. On thespectrum Profile n, there are two cutoff wavelengths λ₁ and λ₂. λ₁ andλ₂ will be selected to be the desired wavelength range for a particularclass or set of light-activated materials for which the light may beused, and the light will be able to activate light-activated materialssensitive to light between λ₁ and λ₂. For example, a light source withλ₁=400 nm and λ₂=460 nm might provide an appropriate light spectra foractivating current dental materials. The spectrum profile has twointensities relative to cut off wavelength, I₁ and I₂. The value of I₁and I₂ can be I₁>I₂, I₁<I₂ or I₁=I₂, as desired. The spectrum profilebetween I₁ and I₂ can be linear, parabolic and others, as desired.

[0123] If desired, a curing light can be constructed per FIGS. 39 and 40in which the peak spectral output of most or each chip is in the rangeof between 200 and 455 nanometers, so that λ₁>=200 nm and λ₂<=455 nm.Another variation would place λ₁>=300 nm and λ₂<=455 nm. Light intensityoutput from each chip can be as desired, such as 40 mW or more, and insome configurations intensity I₁ and I₂ will both equal or exceed 40 mW.There is no upper limit for light intensity other than ordinaryengineering constraints.

[0124] Heat sinks are often a combination of two different kinds ofmaterials, the first with a low thermal expansion rate and the secondwith high thermal conductivity. Monolithic heat sinks may be used aswell. Examples of some heat sink materials which may be used in lightsdepicted herein include copper, aluminum, silver, magnesium, steel,silicon carbide, boron nitride, tungsten, molybdenum, cobalt, chrome,Si, SiO₂, SiC, AlSi, AlSiC, natural diamond, monocrystalline diamond,polycrystalline diamond, polycrystalline diamond compacts, diamonddeposited through chemical vapor deposition and diamond depositedthrough physical vapor deposition, and composite materials or compounds.Any materials with adequate heat conductance and/or dissipationproperties can be used. If desired, a heat sink may have fins or othersurface modifications or structures to increase surface area and enhanceheat dissipation.

[0125] Examples of heat conductive and/or electrically insulativeadhesives which may be used are silver based epoxy, other epoxies, andother adhesives with a heat conductive quality and/or electricallyinsulative quality. In order to perform a heat conductive function, itis important that the adhesive possess the following characteristics:(i) strong bonding between the materials being bonded, (ii) adequateheat conductance, (iii) electrically insulative or electricallyconductive if desired (or both), and (iv) light reflectivity if desired,or any combination of the above. Examples of light reflective adhesiveswhich may be used include silver and aluminum based epoxy. One exampleheat conductive and electrically insulative adhesive includes a mixtureof a primer and an activator. In this example, the primer may containone or more heat conductive agents such as aluminum oxide (about 20-60%)and/or aluminum hydroxide (about 15-50%). The primer may also containone or more bonding agents such as polyurethane methacrylate (about8-15%), and/or hydroxyalkyl methacrylate (about 8-15%). An activator maybe mixed with the primer to form an adhesive. The activator may includeany desired catalyst, for example n-heptane (about 5-50%),aldheyde-aniline condensate (about 30-35%), isopropyl alcohol (about15-20%), and an organocopper compound (about 0.01 to 0.1%). Adhesivessuch as described herein can be used to mount a chip to a primary heatsink, or to mount a primary heat sink to a secondary heat sink, or both.

[0126] Examples of substrates on which the semiconductors used in thelights depicted herein may be grown include Si, GaAs, GaN, ZnS, ZnSe,InP, Al2O3, SiC, GaSb, InAs and others. Both electrically insulative andelectrically conductive substrates may be used.

[0127] Materials which may be used in a thermoelectric cooler in lightsdepicted herein include Bi₂Te₃, PbTe, SiGe, BeO₂, BiTeSe, BiTeSb, AlO₃,AlN, BaN and others.

[0128] The semiconductor light source of a light should emit light of awavelength suitable to activate the desired light-activated material.This may be achieved by using a semiconductor light source that emits awavelength of light to which the light-activated material is sensitive,or emitting a shorter wavelength of light at a higher power level.Laboratory testing shows that using a wavelength of light that is longerthan the wavelength to which the light-activated material is sensitiveis often not effective in activating the light-activated material.

[0129] Heat sinks used in the lights can be of a variety of shapes anddimensions, such as those depicted in the drawings or any others whichare useful for the structure of the particular light source beingconstructed. It should be noted that particular advantage has been foundwhen attaching the semiconductor light source to a small primary heatsink, and then the small primary heat sink is attached to an elongatesecondary heat sink to draw heat away from the semiconductor and awayfrom the patient's mouth.

[0130] While the present lights have been described and illustrated inconjunction with a number of specific configurations, those skilled inthe art will appreciate that variations and modifications may be madewithout departing from the principles herein illustrated, described, andclaimed. The present invention, as defined by the appended claims, maybe embodied in other specific forms without departing from its spirit oressential characteristics. The configurations of lights described hereinare to be considered in all respects as only illustrative, and notrestrictive. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

1. A light for activating light-activated materials comprising: a wandadapted to be grasped by a human hand for use in positioning andmanipulating the light, a wand housing that is at least a portion of theexterior surface of said wand, said wand housing having a top, a bottom,a left side and a right side, an elongate heat sink located at leastpartially within said wand, said elongate heat sink having a proximalend, a distal end, and a longitudinal axis therebetween, at least onesemiconductor chip capable of emitting light of a wavelength that isuseful in activating light-activated materials, said semiconductor chipbeing located at said elongate heat sink distal end, a cover forcovering said chip, said cover being made at least in part from amaterial that permits light emitted by said chip to pass through saidcover to travel to a light-activated material, a plurality of insulatorslocated between said heat sink and said wand housing, an air jacketlocated between said heat sink and said housing, said air jacket atleast partially surrounding said heat sink, said air jacket permittingair circulation, ventilation and heat dissipation in order to manageheat given off by said chip.
 2. A curing light as recited in claim 1wherein a material of at least one of said insulators is selected fromthe group consisting of rubber, silicone and plastic.
 3. A curing lightas recited in claim 1 further comprising a vent on said housing throughwhich air from said air jacket may flow.
 4. A curing light as recited inclaim 1 further comprising a vent on said housing which permits air fromoutside of said housing to flow to said air jacket.
 5. A light foractivating light-activated materials comprising: a housing, asemiconductor chip capable of emitting light useful in activating alight-activated material, a primary heat sink, said semiconductor chipbeing attached to said primary heat sink, a secondary heat sink capableof assisting in heat dissipation, said secondary heat sink being locatedat least partially within said housing, a plurality of insulatorslocated between said secondary heat sink and said housing, saidinsulators serving to form a gap between said secondary heat sink andsaid housing, said gap forming an air jacket that at least partiallysurrounds said secondary heat sink, said air jacket serving to mitigateagainst conductance of heat from said secondary heat sink to saidhousing, air located in said air jacket.
 6. A curing light as recited inclaim 5 wherein a material of at least one of said insulators isselected from the group consisting of rubber, silicone and plastic.
 7. Acuring light as recited in claim 5 further comprising a vent on saidhousing through which air from said air jacket may flow.
 8. A curinglight as recited in claim 5 further comprising a vent on said housingwhich permits air from outside of said housing to flow to said airjacket.
 9. A light for activating light-activated materials as recitedin claim 5 wherein the mass of said secondary heat sink is greater thanthe mass of said primary heat sink.
 10. A light for curinglight-activated materials as recited in claim 5 further comprising: alayer of heat conductive adhesive located between said primary heat sinkand said secondary heat sink, said layer of heat conductive adhesiveserving to conduct heat from said primary heat sink to said secondaryheat sink for dissipation, and said layer of heat conductive adhesiveserving to permanently affix said primary heat sink to said secondaryheat sink.
 11. A light for activating light-activated materials asrecited in claim 5 further comprising a thermoelectric cooler located onsaid secondary heat sink, said thermoelectric cooler serving to assistin heat dissipation.
 12. A light for activating light-activatedmaterials as recited in claim 5 wherein said chip is selected from thegroup consisting of light emitting diode chips, laser chips, lightemitting diode chip array, diode laser chips, diode laser chip array,surface emitting laser chips, edge emitting laser chips, and VCSELchips.
 13. A light for activating light-activated materials comprising:a housing having a top, a bottom, a left side and a right side, a lightemission control actuator which when actuated causes light to be emittedfrom the light for activating light-activated materials, said lightemission control actuator being located on one of said housing left sideand said housing right side, a secondary heat sink capable of assistingin heat dissipation, a primary heat sink attached to said secondary heatsink, a semiconductor chip capable of emitting light useful inactivating light-activated materials materials, said chip being mountedto said primary heat sink, at least one insulator located between saidsecondary heat sink and said housing, an air jacket formed by a spacebetween said secondary heat sink and said housing, said air jacketserving to avoid conductance of heat so said housing.
 14. A curing lightas recited in claim 13 wherein at least one of said insulators includesa material that is selected from the group consisting of rubber,silicone and plastic.
 15. A curing light as recited in claim 13 furthercomprising a vent on said housing through which air from said air jacketmay flow.
 16. A curing light as recited in claim 13 further comprising avent on said housing which permits air from outside of said housing toflow to said air jacket.
 17. A light for activating light-activatedmaterials as recited in claim 13 wherein the mass of said secondary heatsink is greater than the mass of said primary heat sink.
 18. A light foractivating light-activated materials as recited in claim 13 furthercomprising a thermoelectric cooler located on said secondary heat sink,said thermoelectric cooler serving to assist in heat dissipation.
 19. Alight for activating light-activated materials as recited in claim 13wherein said chip is selected from the group consisting of lightemitting diode chips, laser chips, light emitting diode chip array,diode laser chips, diode laser chip array, surface emitting laser chips,edge emitting laser chips, and VCSEL chips.
 20. A light for activatinglight-activated materials as recited in claim 13 further comprising adome over said chip.